Completed formula parsing and evaluation components. Could do with more testing however.
Documented the parser a bit more.
Added some more documentation. Changed how functions are accessed.
All interface methods implemented, parameters now handled
Merge branch 'LauraLexer' into jake/GUI
Adds the first version of the GUI, with the ability to save graphs as PNG files. Needs testing on non-Macs.
Fixed the parser up to handle negations properly. Tested charting on Linux.
Messed up something in the parser. It now works properly.
Switched to using BigInteger where possible to handle exceeding the double limitations.
Adds "from" and "to" values, incrementer values, "about" window and help screen.
Merge branch 'master' into jake/GUI

Conflicts:
	MathsThing_GUI/src/uk/ac/uea/mathsthing/gui/GUI.java
Removes incrementer option, fixes up the UI a bit.
Switched parser to use Token types rather than Strings.
Merge branches 'LauraLexer' and 'jordan/parser' into LauraLexer

Conflicts:
	MathsThing_GUI/src/uk/ac/uea/mathsthing/Lexer.java
Fixed the parser to allow it to build evaluation trees with functions embedded.
lexer updated to use enums, interface and tests upfated to reflect change
Merge branch 'jordan/parser' into LauraLexer
Fixed the pattern matching being in the wrong order.
fixed lexer regex once more to handle functions properly.