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.
Correct logError to log err which has undefined `message`

closes #4384
 - if err is `object` && `err.message` isNOT `string`, let err = `An unknown error occurred.`
Merge pull request #4384 from meowtec/fix-error-log

fix bug in which `logError` could not resolve an err without `message`
Remove hash after the url when clicking Meta Data

Removes that hash appended to the URL when clicking Meta Data in post settings.

Closes #4386

When clicking 'Meta Data' the click event appends a # to the URL. I replaced the a with a button element so that won't happen anymore. The button has a type attribute because it will try and submit the form without it. Added text-align: left to the navlist button because the button centers it's content by default.
Merge pull request #4405 from jillesme/iss-4386

Removes hash after the url when clicking Meta Data
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.
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