Point to GitTip instead of Pledge.
Added getline.cs to project.
Modified getline.cs to work with already written prompt, integrated it in user interface of Pash, made optional with variable.
Added new file for testing the ui.
Added unit tests for user interface that work with limitations

The unit tests work with the nunit IDE plugin. However, with nunit-console and nunit-gui they
do not work, as Console.SetIn() doesn't work as intended. Instead it's waiting for user input.

The second limitation is that running these tests with nunit will never test the getline-based ui.
This is because nunit doesn't run in a terminal emulator and thus properties like Console.WindowWidth
are 0, so getline.cs isn't usable.

I hope that some of the limitations can be overcome in the future, s.t. more unit tests can be added.
Merge pull request #170 from sburnicki/getline_integration_take2

Getline Integration - Take 2
Add information about TERM issues.
Merge pull request #172 from ForNeVeR/doc-fix

Add information about TERM issues.
Enable BindingCombinationNonDefaultSet test
Changed MonoDevelop specific settings to fit the code formatting of VisualStudio
Merge pull request #175 from sburnicki/monodevelop_codeformat

Changed MonoDevelop specific settings to fit the code formatting of VS
Replace general throw Exception for Parameters binding by ParameterBindingException
Revert exception type for ambiguous parameter from ParameterBindingException to ArgumentException
Allow variables inside double quoted strings.

Example: "$foo"
Implement AST for variables inside an expandable string.

Simple variables inside a double quoted string are added to the
expandable string's nested expressions.
Merge pull request #174 from vors/master

Enable BindingCombinationNonDefaultSet test
Introduced scope class to change architecture to support scopes

Pash's architecture had no support for scopes. Instead, there was just
one global scope. These changes are the start of scope implementation.

While the "global scope" bahvior isn't changed, yet, the architecture
is changed to support scopes in regard to variables and drives.
The new class, SessionStateScope, is the new heart of a SessionState
and is intended to support nested scopes. The SessionStateGlobal class
is intended to care about the not-scope related things as providers.
An important change is that SessionStates aren't simple copy-objects
that are created every now and then, but only if it's really necessary.

There are further steps that need to be done to fully support scopes:

* While VariableIntrinsics and DriveManagementIntrinsics already implement
  the new scope behavior, the alias and function scope support still has
  to be added.

* Once this is completed, the creation of SessionStates has to be adjusted even
  more in order to correctly create new scopes.

* The existing cmdlets (new-variable, etc) need to be re-written to better
  support scopes, read-only flags, etc.

* There should be some refactoring of existing code. SessionState should
  be used as a central object to modify the sessions data.
Merge pull request #176 from sburnicki/scopes

Introduction of scopes
Implement script extent for parse tree nodes.
Add script extent for nested expressions inside expandable strings.