moving as many pester tests to new assertions
adding Should Match and updating Pester tests
all Pester tests use new assertions
enabled workaround that fixes #19 and fixes #27

Pester itself is using the new assertion format. So if you only
use those you can disable the old style assertions which have been
causing these issues.

The flag is -DisableOldStyleAssertions

For backwards compatibility these will be enabled by default.

For release 2 of Pester, these will be disabled by default and you
will have to explicitly enable them.