Allow static members to be called from type stored in variable.

Supports the following statements:

[Environment]

$path = [System.IO.Path]
$path::GetDirectoryName($project.FileName)
REFACTOR: Remove duplicate code when visiting static members.
TEST: Use TestCase in -eq tests.
Support using $null, bools and strings with -eq operator.
Make -eq case insensitive for strings.
Implement -ge for integers.
Implement -not operator.
Implement -match operator.
Support using indexer on hash table.
Set $matches variable for -match operator.
Support using 'exit' to stop script execution.
Support function parameters in AST.
Implement try catch.

Supports try catch all and allows the use of the error record inside the catch:

try {

} catch {
    Write-Host $_.Exception
}
Merge pull request #151 from mrward/executing-ast

Support a few more statements in PowerShell scripts