Add pg as an optional dependency.

Closes #1333
- Change PostgreSQL build on Travis from an allowed failure to
  failing the tests just like sqlite3 and MySQL.
Adds SIGTERM handling

closes #4403
- adds SIGTERM handler to match SIGINT handler
Merge pull request #4404 from Haegin/add-sigterm-handler

Adds SIGTERM handling
Remove image related text from meta description.

Closes #4408
Merge pull request #4395 from jaswilli/pg

Add pg as an optional dependency.
Use pure javascript library for postgresql.
Merge pull request #4410 from jaswilli/issue-4408

Remove image related text from meta description.
Change Numeric Keyboard to Keypad

Added pattern to html to make the keyboard a keypad

Closes #4426

    Added pattern="[0-9]*" to the postsPerPage input on general.hbs
Merge pull request #4422 from jaswilli/pg

Use pure javascript library for postgresql.
Merge pull request #4427 from dbalders/master

Change Numeric Keyboard to Keypad
Reset slugValue when the user changes

Closes #4411
- Previously, saving the user’s slug would lead to the slug value being
‘stuck’ on that saved value, even if one navigated to a different
user’s profile settings.
Merge pull request #4428 from felixrieseberg/iss4411

Reset slugValue when the user changes
Drop socket reference on close.

Closes #1976
- Prevent the unbounded memory growth caused by maintaining
  a reference to the socket object that is created on every connection.
Merge pull request #4430 from jaswilli/leak

Drop socket reference on close.
full BREAD Tag endpoints and Tag api tests

close #4263
- implemented full BREAD Tag API
- deleting a tag will also detach its relations to posts
- tests of Tag API
Update dependencies

Refs #4240
- grunt-mocha-cli@1.11.0 (v0.12 support)
- moment@2.8.3
- knex@0.7.3
- express@4.10.2
- validator@3.22.1
Merge pull request #4437 from jaswilli/deps

Update dependencies
Work with case-sensitive email addresses

Closes #4235
Merge pull request #4320 from felixrieseberg/iss4235

Work with case-sensitive email addresses
Merge pull request #4406 from RaoHai/tag-endpoints

full BREAD Tag endpoints and Tag api tests