Improved parsing of biomolecular transformations.

Continuation lines listing chains are now parsed.
Updated change log [skip ci].
Added option to match non-hydrogen atoms.
Skipping hydrogen atoms when matching heavy atoms.
Updated change log [skip ci].
Merge branch 'devel' of github.com:prody/ProDy into devel
Added Python 3.3 for testing.
Added/revised tutorial files [skip ci].
Changed unittest imports so unittest2 can be used when available in py 2.6.
Revised Python 3.3 requirement installations.
Added Py 2.6 to Travis CI, revised tests.
Enabled gzip wrapper for Py 3.3.
Enabled tests for py 2.6, revised travis ci required pkg installations.
Fixed a problem with adding test app.
Fixed requirement installation problems for py 3.3.
Added an odds option to prody test command to run full tests sometimes.
Converting float inside range function to int for Py 3 compatibility.
Simplified requirement installations.
Changed with statement for py 2.6 compatibility.
Fixed memory problem resulting from incorrect parsing of int value.