IMT objects are now pickleable
Fixed a docstring
Merge pull request #146 from gem/imt-pickleable

IMT objects are now pickleable
Minor fix in the imt module
Moved the tests inside the package
Renamed a script
Merge pull request #147 from gem/move-tests

Moved the tests inside the package
Merge branch 'master' into bjf1997_gmpe
Merges upstream changes, adds docs, pep8 fixes