build: remove old python prototype.
build: remove Python.m4 from configure.
memory: add bson_mem_set_vtable()

This function allows setting a custom memory allocator. It must be called
at the beginning of the process so that allocations are allocated and freed
by the proper system.
context: use statically allocated default context.

This removes the need for the atexit() handler.
context: remove superfluous malloc
context: protect against destroying the default context.
Fixed typo in json-to-bson documentation.

Some comments in json-to-bson.c were the same as in bson-to-json.c. Some
BSON and JSON's needed to be switched.
Merge pull request #78 from mwhittaker/example-typo

Fixed typo in json-to-bson documentation.
Release 0.98.0!

Signed-off-by: Christian Hergert <christian.hergert@mongodb.com>
build: post-release bump.