Fix issue with Rakefile deploy task.

- Deploy task was not formed correctly.
- The if conditionals did not make any sense (was not checking configuration correctly at all).
Add dependency on build with deploy task.

- Remove deprecated --no-auto in build task.
Add ability to exclude files from rsync.

- In config, define files/folders to be excluded.
- When building rsync command, loop over the exclude_list config option.
Use exclude command from Jekyll to ignore files during build.
Use array for exclude_list config option.

- Add better error message and return early if config options could not be validated.
Add email icon and title attributes to social links.
Change styling of fonts and headings.

- Change post title font-size.
- Add margin to headings.
- Add letter-spacing of 1px.
Restructure footer CSS styling.

- Move social selectors under footer.
- Add padding to the right of the copyright message to match the social offset.
Remove link to Tags page.