Fixing output and internals

- Fix Pester template self-tests [GH-113]
- Time is output to the XML report [GH-95]
- Internal fixes to remove unnecessary dependencies among functions
Fixing internals for Vista

Forgot to test the previous commit on Windows Vista (PowerShell v2)
before pushing.
Clean up Invoke-Pester interface

Standard PowerShell cmdlets use singular nouns for their Parameters and
standardized set of parameter names like 'Path'. Changing Invoke-Pester
interface to reflect this. To keep backwards compatibility the changed
parameters are aliased.
Make output better structured

Moving the margin before the [+] in the test output. This makes for a
tree-like structure in which it is easier to see what tests are in
Describe and what are in Context
Add PassThru option to Invoke-Pester

When called with -PassThru the Invoke-Pester returns object on exit. The
object contains information about the whole run and about each test.
Fixes Bug #114: New-Fixture raises exception when using $pwd directly as -Path parameter.
Restricts parameters to [string] instead of letting powershell decide which datatype to use
Merge branch 'fix_exceptions_in_new-fixture'
New-Fixture standardized

- Accept and resolve paths on input as other cmdlets do.
- Output standard objects.
- Using only Name parameter you can create fixture in the current
directory .
- If file exists Warning is issued.
- Numerous internal amendments to make the function easier to read.
- Adding Tests

- not moving the function out of Pester.psm1 to make the changes easier
to track.
Move New-Fixture out of Pester.psm1

- Moved New-Fixture and Create-File to separate script file
- Discarded Write-UsageForNewFixture. Usage can be looked up by
Get-Help, so inline help becomes the only place to update if interface
changes.
Fix tag filter

Fix the tag filter that I broke. We really need a test for this.
marking the 2.0.4 release
updating docs to use latest should syntax
Fixing hash signs in Describe name

Fixing issue introduced in 605ee37bf079b08be33d6931cb1260921acc91fa.
Hash tags placed around Describe name in auto-generated test files.
Updated local changes with upstream changes