Reported by Ron Proctor

netrender didn't recursively create missing directory for user specified temporary paths.

Also added environment variables and user expansion to properly support env vars and user (~ and ~user) in paths.

change to the repatching and local naming algorithms to better support different files with same name and dependency folder hierarchies.

Support for secure connections between Master/client/slave using SSL/HTTPS

Fixed a bug with total job time on web interface (wrong value)

- distributed point cache baking
- (baking fluids or anything else needs to be added but is not a hard task)
- master support getting all results as a zip (rendering, baking or otherwise), available as a link on the job's page in the web interface
- framework to support multiple result files per frame/task (needed for baking)

wip feature: distributed point cache baking. Distributed baking works but results are sent back to master/client yet. Feature is disabled in the UI for this reason.
new feature: job and slave tags, enables filtering slaves for specific jobs
  jobs are dispatched to a slave only it has no tags or all the job's tags
  Render jobs have the tag "render" by default while baking jobs the tag "baking"
UI: Web interface additions to reflect tags and job subtypes (render/baking)
bug fix: reseting a completed job correctly resets the status to queued

- Support for dynamic painting point cache (patch by Philippe Van Hecke)
- Fix job log name generation to not exceed filename limits when using large chunks
- Cleaning up duplicated code for point caches, fluid and multires between client and repath module

- fix handling of pointcache dependencies on slave (correct repathing) and on client (bad frame dependency range)
- add Force Upload option on master to force dependencies upload and download (don't reuse local copies outside of slave cache)
- add links back to main page on job web page
- client limit dependencies to rendered frame range (it used to add all point cache frames)

Thanks to Philippe Van Hecke for raising the issue by email.

Fix for #26867

Hunted down and debugged with great help from Geoff Murphy

* Scan for master failed and gave an script error. 

exception safeguard in render engine
fix module import broken by someone else

- remove/comment unused variables
- remove unused imports
- fixed some bugs using incorrect variables

better stream handling when uploading files
Might solve the problem with OS X masters