Create a "stable" branch for use by docs and scripts

[oubiwann]

When the branch is created, the following tickets can use it and then be closed:

• 109 - Update project README and Quickstart with new download URL

• 113 - Update the "lfetool update" command to point to the right release

This need for this ticket was discussed in issue #111.

[dokkarr]

Proposal for branch re-org:

• create "stable" from branch "milestone-v1.2"
• create "dev-v1" from branch "milestone-v1.3" (merge to "stable" when milestone 1.3 is complete)
• create "dev-v2" from branch that is currently named "develop"

Other suggestions:

• make "stable" the default in the UI.
• document somewhere that "master" is really just another name for "legacy"; we could delete it once v3 is released ...
• clean up remaining branches (i.e., delete them)

[dokkarr]

This has been done, now:

• branches renamed
• v1.3 has been tagged and pushed, and merged to stable
• new milestone 1.4 has been created
• LFE 0.9.0 support tickets have been moved to milestone 1.4

More cleanup ahead, but will close.

Remaining tasks:

• update the version of dev-v1 to 1.4.0-dev
• update wiki pages and READMEs to point to stable instead of the old branches that they currently point to
• try to merge stable to dev-v2
• work on 1.4.0 to support LFE 0.9.0.