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.
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.