added correlation to linalg
Merge branch 'master' of https://github.com/qminer/qminer
Merge pull request #63 from lrei/master

 	added correlation to linalg
Merge branch 'master' of github.com:qminer/qminer
store.getColumn(fieldName), store.cell(recId, fieldName)
string vector, vector serialization (binary, matlab), graph neighbor accessors

store.cell(recId, fieldName) is more efficient than store[recId].fieldName