Read the pid only once when stopping an instance

Review 718 by @mlucy
Closes #1115 again
Making the wording more clear, OTS review by @atnnn
config file parsing will now ignore options that apply to other modes of rethinkdb
added warning in must specify one of --directory or --file to import when unexpected files are found in the import directory
fixed a problem with nice_crash not logging errors properly, although it's pretty ugly right now
stopped using nice_crash in exceptions, just because it's a little silly, unified address in use exception catching, and fixed a bug in object_buffer_t when create() causes an exception
Removed nice_crash and nice_guarantee, since their use case is questionable at best.  Replaced with clean exits, or regular crashes.
Create /var/run/rethinkdb with the correct mode

Review 719 by @tryneus
Closes #1069
Tell launchpad to include the debug symbols

Review 731 by @tryneus
Closes #1130
Fix python version detection in proxy.sh

Review 732 by @tryneus
Closes #1165
Fix body for . ROTS by @mglukhovsky
1155_fix_wire_func_serialization
Merge branch 'v1.7.x' into next

Conflicts:
	src/arch/types.hpp
	src/clustering/administration/main/serve.cc
	src/clustering/administration/main/serve.hpp