* adds certificate store location
* add additional certificate store tests
* add cert store tests for New-CredentialStoreItem
* fix test
* add error handling for credential store path
* add Import-CSCertificate helper function
* Import new certificate if param is given
* fix extension filter
* add linux error message
* fix pester test for linux
* update cert helper functions
* export helper functions
* fix cs cert import
* simplify cs cret lookup
* remove obsolete functions
* fix pester test for linux
* fix error type for linux
* fix var name
* fix pester test
* disable travis artifact upload
* update cert lookup for item functions
* debug build error
* use cert instance constructor for linux
* disable debug output
* remove obsolete exports
