Updated makefile
Added code for function parsing
Fixed indentation
Added code to handle function with power
Fixed indentation
Code clean-up
log case handled
Minor fixes
Errors fixed in log calculation
Minor fix in equation-parser.vala
Fix for log
Made FunctionParser inherit from ExpressionParser:Parser
Added ExpressionParser in place of FunctionParser
Fix for function definition overwrite bug
Added function_is_defined
Added function auto-completion
Added function menu
Added tooltip in function menu and some minor fixes
Added variable auto-completion
Fixes for error setting in parser