package private constructor of r classes. fixed variable names parsing from r script
started plot aggregation
Code clean
Merge branch 'master' of github.com:openforis/calc into steptest

Conflicts:
	calc-core/src/main/java/org/openforis/calc/r/RScript.java
	calc-core/src/main/java/org/openforis/calc/r/RVector.java