#31 (made Expression inherit from PositionAwareNode and adapted constructors accordingly)
#31 (Changed all but two calls to sa.reportError() to include position)
#31 (Made return statements position aware)
#31 (fixed warnings)
Introduced typedef std::pair<unsigned int, unsigned int> source_position_t
Revert "#31 (fixed warnings)"

This reverts commit 0f1ab340a70060660d3f3c83f08bee428e546b65.
Merge branch '#31' of https://github.com/djrieger/mjplusplus into #31

Conflicts:
	src/ast/PrimaryExpression.cpp
Added precautionary check for lineNumber == 0 in ErrorReporter.
Added pre-commit hook which can automatically run tests when trying to commit on dev (but tests take too long thus not usable yet)
Merge branch '#31' into dev