fixing behavior when passing a non-directory to --directory
merging #3112 r.http() https access not working on OSX

Conflicts:
	mk/support/pkg/curl.sh
Add 1.15.1 release notes
Updates
committing the configure changes from #3112
Change wording/capitalization
Use latest Ubuntu AMI as base in build AMI script
allow building with protobuf 2.6.0
Add #3137
Fix debian package version and remove build dependency on node
Merge pull request #3135 from rethinkdb/wm-1.15.1-notes

Add 1.15.1 release notes
Bump Python driver to 1.15.0-1
Use collections abc's to be more permissive in what the python driver accepts.
Adds several macros to mark types only serializable for use within the cluster
Expanded on a comment
fix for extra space in get_all test

over-the-shoulder review by @ Tryneus
Fixes two compiler warnings regarding missing return statements in non-void functions, reviewed by @danielmewes
Merge branch 'vexocide/2631' into next
Merge branch v1.15.x into next
merge of #2912 Float rounding issues on polyglot/geo/primitives

from branch larkost/2912-float-rounding