added tests for predicates
added sym matrix predicate test
Operations proof-of-concept
refactored the protorype
introduced the iterators
interators are read-only
test usage added
working on iterators; first draft of intersetion is ready
added VectorIterator.and() draft implementation
playing with opertaions; new operations
reused or;and operations for both iterators
refactored the and;or operatons
refactored the or;and methods
improved the performace of iterators
Merge branch 'master' of github.com:vkostyukov/la4j
Merge branch 'master' into operations

Conflicts:
	src/main/java/org/la4j/vector/AbstractVector.java
removed unused code
Merge pull request #175 from vkostyukov/operations

Operations are ready for integration