Added vim modelines
Fixed gitignore
Added documentation
Added external lines for QED
Fixed spelling mistake
Addded documentation for external lines
Changed layout of comments
Added QCD vertices
Added ghost vertex
Changed naming scheme of Functions
Added QCD propagators
Removed unnecessary color indices in propagators

Renamed leptonPropagator to fermionPropagaror and removed
quarkPropagator
Made feyn.prc look nicer
Fixed spelling mistakes
Added a warning about correct use of indices
Switched to dummy indices
Replaced denom(a) with 1/a
Switched spin from index to symbol
Fixed some documentation errors
Added a readme