Added side channel inputs and constants
Read and write now accept calculated expressions as their parameters; Strings can be added
Added include functionality to meteor and fixed arithmetic expressions
Merge branch 'master' of github.com:AHeise/stratosphere-sopremo

Conflicts:
	meteor/meteor-meteor/src/main/java/eu/stratosphere/meteor/MeteorLexer.java
	meteor/meteor-meteor/src/main/java/eu/stratosphere/meteor/MeteorParser.java
Added boolean constant to boolean expressions