Add message to Emulator startup warning it may take a while.

Add message to Emulator startup warning it may take a while. This
addresses Trac #561.

Change-Id: I5701b43b2523f9d0f888c7b9d88cba8e050cfd95
Adds an outline to the spinner

Some browsers paint the select box with no borders and looks weird, so this
adds and outline to the component (it does not add a border because that would
override the green border painted when a component is selected).

Change-Id: I121a9bd98da8f78fb548532912ea16e9bc2bb6ee
Adds some contributor guidelines to README

Change-Id: I10ddf3e37f85a4af36c9b4575806b91400f3064f
File component to store and read files from external storage

Change-Id: I32e344983285f7d589cd6cec183366b56fc76a22
Update documentation for split blocks.

Change dropdown order for split blocks. Make dropdown change name of
second arg to indicate when input must be a list. Adjust block mode on
reading the XML

Change-Id: Ia93b0c10733502153730ceb7fec798470df77f09
Adds conditionals for list picker and web viewer activities in Manifest

Change-Id: I55ded4ee436da4ea775c3287dbd29ea20b3ead83
Component that wraps the Yandex.Translator service.

Component that wraps the Yandex.Translator service to provide
translations between different languages

Change-Id: If6f435e9d48aaa9d45a18d0fb37320b759123362
Button Enhancements

Added TouchUp and TouchDown events.
FontSize, FontBold, FontItalic properties made visible in blocks editor.

Change-Id: Ia308344c0c660e70f777d035555f77e698d018f6
Fix minor typos in documentation for YandexTranslate

Change-Id: I6e47f1a7ba9d871249dcdb09524f9c0ff5e1227c
Update Companion Version number to 2.18ai2

Change-Id: I671b7f022cf61b156834bb52eef6dce989a3cead
Merge branch 'master' of https://github.com/mit-cml/appinventor-sources
merge privacyinformer branch