dvr.js: Add user-selectable page size for upcoming/completed/failed recordings.
dvr.js: Changed layout to group like options
dvr.js: Cosmetics - Arrange dvr options into like groupings.
config.js: Cosmetics - Arrange options into like groupings.
config_dvr.html: Updated description of caching scheme and attached more up-to-date screenshot for help page.
timeshift.js: Cosmetics - option layout, groupings plus updates to help text and image..
config_misc.html: Cosmetics, spelling/grammar, embedded image.
config_misc.html: Cosmetics, spelling/grammar, embedded image.
Rebase after PR #381

Conflicts:
	src/webui/static/app/config.js
	src/webui/static/app/dvr.js
	src/webui/static/app/timeshift.js
config.js: Code formatting
Webui: Add scroll bars to general config and recording lists (fixes #2113)
timeshift.js: Code cosmetics
Merge pull request #396 from ProfYaffle/master

WebUI tidy-up: Option groupings, updated help text, and user option to determine page size for upcoming/completed/failed recordings.