Add option to display full version in AboutBox

When using a DVCS it's useful to add the SHA1 as revision to the version
number so that it easier to see the state of the code that was used to
build. This can be done by using the AssemblyInformationalVersion
attribute which gets used by Application.ProductVersion.

This change adds the option to display the full version number as taken
from Application.ProductVersion. The default behavior doesn't change and
will still show the short version number (MajorVersion.MinorVersion.Build).
To display the full version number the value TRUE can be passed to the
SILAboutBox c'tor.
Merge pull request #97 from ermshiperete/feature/EnhanceAboutBox

Add option to display full version in AboutBox
Fix crash in (some) custom keyboards

Not all custom keyboard define the country code, which is normally
needed as the basis for the keyboard code.  For those keyboards, the
language code is used instead.
Merge pull request #99 from sillsdev/FixCustomKeyboardCrash

Fix crash in (some) custom keyboards
Add TempFile.WithFilenameInTempFolder()
Use safer way to try to delete temp folder
Merge pull request #101 from JohnThomson/TempFileInTempFolder

Add TempFile.WithFilenameInTempFolder()