do not blow away multiple conformers when adding hydrogens

Added further checks for zlib availability in OBConversion

Also check for possible isotopes (e.g., using D or T instead of H).

More checks were necessary to make all occurrences
of zlib-dependent code build conditional.

Caused problems with substituted purine bases.

Fixed the (HM: 63 m c) to (HM: P 63 m c) in space group data file.

OBConversion improvements

the is new behavior taking advantage of the improved gzip support

Conflicts:
src/obconversion.cpp

Conflicts:
src/obconversion.cpp

clear status on original stream before seeking

need to set auxconv in assignment, this is _not_ a good design pattern

implement assignment operator so ownership of allocated streams remains with one obconversion

this way we are not retaining a pointer to the underlying streambuf, just the user provided stream

still broken

mmcifformat plugin now support atoms occupancy and atom_type category

New option in VASP format. Custom atom sorting.

Don't set precision to 0 when reporting time estimate

Fix for #173

Add support for hardware popcount

Changing the stream precision to 0 seems like a bad idea.

I'd rather see a reported time of 90....

Fix for DeleteHydrogens behaviour #178

Add regression test for fast tanimoto search

I break -at option in a local build, and make test failed to detect
the breakage. Add a regress...

Fix OBStopwatch to return fractional seconds

OBStopwatch was using integer division to arrive at a double,
and so would report only integer s...

Prevents bogus warnings about re-defined command-line options.
Fixes Issue #170.

Remove msvc deps

Fix for #134

Edit ifdef MSVC to be MSVC version specific

Fix for compile error with MSVC 2013.