Merge pull request #26 from charvel/master

New feature: Weather provider can be chosen from Yahoo! and Wunderground
Installer: Fix popup background color
Bug: Restored slider positioning to previous behavior
Installer: Fix rendering bugs and hide API key if not needed
Base: Minor changes
Logs: Fixed bug reporting no entries in table view
Weather: Round Fahrenheit to nearest whole number
Localization: Full Spanish translation by @afields
Preview: Prevent table from showing when data isn't present
Preview: Fix header spacing and use jQM icon's instead
Preview: Change bottom control buttons to use jQM icons

Also removed old icons that are no longer used.
Base: Previous commit missed deleting unused icons
Current Status: Fix bug where status bar wouldn't hide
Settings: Reflowed to separate device vs app settings

A lot of things were rearranged in this commit. Please post on the
forums or on Github issues if a serious issue comes up due to the
rearrangement.
Localization: Update english strings from source
Base: Fix error in variable initialization

Introduced in prior commit
Readme: Provide more complete install instructions

Also, specified web server requirement in overview.
Rain Delay: Changed home page link to popup

because automatic rain delay got moved to application settings under
weather settings. This was done to consolidate and distinguish device
settings from application settings.
Base: Changed loader icon to use CSS instead
Base: Fixed loading icon margin issue within weather div