This change adds a new documentation file called troubleshooting.md which
gives the user guidance on how to resolve commonly occuring problems when
using this extension. For now it just contains information on how to
install OpenSSL when using the extension on OS X.

This change adds a check when the extension initializes to verify
whether the machine has OpenSSL installed when running on OS X. This is
currently a requirement of PowerShell which must be met before
PowerShell Editor Services can be started. If the proper library paths
are not detected, a message is shown to the user which leads them to
documentation on how to install OpenSSL.