Latools

Added clear_subsets function
Re-aligned pypi versions after snafoo.

Fixed type error thrown after numpy update.

No longer fails if analytes are missing from SRM database.

Fixing minor bugs introduced in 0.3.10. General cleanup, added makefile.

Changed
- Fixed broken meta_regex parsing when key was numeric instead of str.
- Fixed default behaviour of mass fraction calculation
- Removed extrapolation from interp1d background calculation to avoid negative backgrounds/stderrs.

Plus minor tweaks and bug fixes throughout.