Start of solution generation algorithm
Implemented HashCash. Broke a lot of stuff which was "using" it.
Fixed checkZeros function bit checking
Continued with HashCash (added identification, did some fixes, made exceptions more logical)
Wrote tests for HashCash.
Some negative tests for HashCash.
Small fix in checkZeros
Added some temporary methods for testing in Challenge and Solution.
Continued with negative tests of HashCash.
Changed the notion of "id" of a Challenge to "purpose".
Simplified and expanded the HashCash main class.
Made TaskPasser to at least compile with the implementation of HashCash.
Small fixes in Challenge.
Made checkZeros use BitSets instead of looping through byte arrays.
Continued with testing. Everything seems to be working now!
Fixed some comments.
Merge branch 'hashcash' into development

Conflicts:
	GDCN_proj/Client/src/main/java/network/TaskPasser.java