VocabLib/include/InvertedIndex.hpp
* In classes ImageCount, Word and InvertedIndex, moved above their
attributes declaration.
* In classes ImageCount and Word, declared and defined equality and
inequality operators.
* In class InvertedIndex, renamed methods to save/load index.

VocabLib/src/InvertedIndex.cpp
* In equality method of class InvertedIndex, refactored in order to use
ImageCount and Word equality/inequality operators.
* In class InvertedIndex, renamed methods definition according to their
declaration.
* In class InvertedIndex, removed calls using this keyword.
* In class InvertedIndex, refactored load method to remove assumption
that words exist beforehand.

VocabLib/tests/InvertedIndex_test.cpp
* Refactored tests according to changes in ImageCount, Word, and
InvertedIndex classes.
* Implemented test for InvertedIndex save/load methods.
* Moved to the bottom InvertedIndex test methods.

.cproject
* Generalizing include path for k-majority library by using eclipse
environment variables.