PowerShell 6 Core Support (#35)

## About
This pull request reflects all changes done in the `linuxsupport` branch.

## Content
- Enable PowerShell 6 Core support
- Use PFX Certificate for encryption ( fixes #32 )
- Updates CI / CD pipeline ( fixes #31 )
- uses portable libressl ( fixes #34 )
- adds `-PassThru` switch for returning current `VIServer` session in `Connect-To` ( fixes #34 )
- adds git lfs for embedded libressl files
- restructured internal functions into `Private` dir
- added certificate related functions
- adds travis build pipeline for tests

.vscode/launch.json

@@ -1,48 +1,48 @@
-{
-    // Use IntelliSense to learn about possible attributes.
-    // Hover to view descriptions of existing attributes.
-    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
-    "version": "0.2.0",
-    "configurations": [
-        {
-            "type": "PowerShell",
-            "request": "launch",
-            "name": "PowerShell Launch Current File",
-            "script": "${file}",
-            "args": [],
-            "cwd": "${file}"
-        },
-        {
-            "type": "PowerShell",
-            "request": "launch",
-            "name": "PowerShell Launch Current File in Temporary Console",
-            "script": "${file}",
-            "args": [],
-            "cwd": "${file}",
-            "createTemporaryIntegratedConsole": true
-        },
-        {
-            "type": "PowerShell",
-            "request": "launch",
-            "name": "PowerShell Launch Current File w/Args Prompt",
-            "script": "${file}",
-            "args": [
-                "${command:SpecifyScriptArgs}"
-            ],
-            "cwd": "${file}"
-        },
-        {
-            "type": "PowerShell",
-            "request": "attach",
-            "name": "PowerShell Attach to Host Process",
-            "processId": "${command:PickPSHostProcess}",
-            "runspaceId": 1
-        },
-        {
-            "type": "PowerShell",
-            "request": "launch",
-            "name": "PowerShell Interactive Session",
-            "cwd": "${workspaceRoot}"
-        }
-    ]
-}
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "type": "PowerShell",
+            "request": "launch",
+            "name": "PowerShell Launch Current File",
+            "script": "${file}",
+            "args": [],
+            "cwd": "${file}"
+        },
+        {
+            "type": "PowerShell",
+            "request": "launch",
+            "name": "PowerShell Launch Current File in Temporary Console",
+            "script": "${file}",
+            "args": [],
+            "cwd": "${file}",
+            "createTemporaryIntegratedConsole": true
+        },
+        {
+            "type": "PowerShell",
+            "request": "launch",
+            "name": "PowerShell Launch Current File w/Args Prompt",
+            "script": "${file}",
+            "args": [
+                "${command:SpecifyScriptArgs}"
+            ],
+            "cwd": "${file}"
+        },
+        {
+            "type": "PowerShell",
+            "request": "attach",
+            "name": "PowerShell Attach to Host Process",
+            "processId": "${command:PickPSHostProcess}",
+            "runspaceId": 1
+        },
+        {
+            "type": "PowerShell",
+            "request": "launch",
+            "name": "PowerShell Interactive Session",
+            "cwd": ""
+        }
+    ]
+}