Merge pull request #1 from merces/master

Adding Makefile (tnx merces!)
Added travis.yml, removed legacy code, added #ifndef to many constants
Changed from indented to fenced code blocks
Added syntax highlighting and build status
Fixed travis-ci build image
Fixed documentation (outplus_dump_*)
Fixed syntax highlighting
Added error checking and changed functions to return int (for error handling) and modify objects passed by parameter
Changed OUTPLUS_LINE and _SECTOR structure. Defining pointers type after. Placed casts where needed. Compiling with -Wall now!
Fixed all the mess I made
Better slug function
Tests added
Fixed test script
Updated docs
Updated docs with full sample code
Added output examples
Fixed json bug, fixed docs and examples
Updated docs, fixed typo