Remove NS_DESIGNATED_INITIALIZER

Caused an error in 6.0.1
Add .gitignore
Move instance vars to implementation
Streamline the IBOutlets

Use weak properties for all outlets (apart from NSTextView that doesn't
support weak). Also, move all to the implementation files instead of in
the public API.
Don't expose IBActions in the public headers

Interface builder will pick them up from the implementation files these
days so no need to expose them as public API when not used by any other
code.
Style fixes

Some style fixes while getting to know the code.
Remove instance variables that only back properties

Let them be automatically synthesized instead.
Remove legacy instance variables and synthesize
Streamline style a bit

- Code was a mix of "-(void)foo" and "- (void)foo" (went for latter)
- Remove the ; at the end of methods
Use CocoaPods for CorePlot instead of submodule
Install CocoaAsyncSocket through CocoaPods

Instead of having a copy in the project.
ACEView for syntax highlighter and proper editor

First step towards getting a better editor for writing the Nu code in place.

Use submodules for ACEView
Fix the resizing of send command button