Changing inputfile so that it can be properly tested (not finished).
Merge branch 'my_changes' into merging_branch

Conflicts:
	abipy/htc/inputfile.py
Quick fix to remove some obsolete imports from pymatgen.
Quick fix to remove some obsolete imports from pymatgen.
Fixed representation of signed integers in the input file.
Merge pull request #14 from GkAntonius/master

Reorganized abipy.htc.inputfile
 Start to move flow factory functions to pymatgen.
 Import upstream (Gabriel's modifications)
 There was a problem with htc/tests/test_inputfile.py (Added to the branch)
Merge branch 'master' of https://github.com/gmatteo/abipy
 This version passes the tests with my pymatgen branch: a5e6bb1ec7d3005fcad25a82f1fff6e0009ed2e6