removed dependencies: igraph and foreach

These are only required in specific circumstances, and were the result of some persistent warning messages, and even an error when working on the hpc (this will be tested with new dev version).
fixed bug in getSceneinfo

LT4 not recognized because of small error in if statement
Minor documentation fixes to processLandsat and processLandsatBatch
Removed ellipsis limitation to only filename and overwrite. Now in principles all arguments of writeRaster() should work.
Tests OK, the new version of mc.calc seems stable; reoxygenized the package
Merge branch 'feature-mc.calc-ellipsis' into develop
Added option to not order scenes chronologically when creating the timeStack (timeStack() function)
Merge branch 'master' of https://github.com/dutri001/bfastSpatial into develop
Changed readme to fit will new devtools arguments and deprecated arguments
Added rgdal to list of dependencies
New version, to be merged in master branch
Merge branch 'develop'