feat(MainActivity): Added Start and Stop Buttons to control recording

Also added some more UI Elemnts which are disabled until the functionality
behind it is ready.

Closes https://github.com/psycholold/SensorReader/issues/1
style(SensoreReader): Code Formatting
refactor(MainActivity, SensoreReader): Remove FileWritingActivity Interface

No need to keep it around. It's simpler if the SensorReader works with a
simple OutputStreamWriter to transmit its data.

Closes https://github.com/psycholold/SensorReader/issues/4
Merge branch '4-refactoring' into tmp-1-4-button-and-refactoring

Conflicts:
	app/src/main/java/shrine/sensorreader/MainActivity.java
style(MainActivity): Style to match device theme and size improvements
feat(MainActivity): Block UI while Recording

This blocks the UI while sensor data is being recorded.
chore(Project): Add .gitignore file to project

At the moment it only ignores the build directory. Additional files can be added as
we move along.
feat(MainActivitd): Get OutputStream writer based on radio button selection

This is a WIP of https://github.com/psycholold/SensorReader/issues/3
Although the network stream is just stubbed the rest is still working as
expected.
Merge pull request #9 from psycholold/tmp-1-4-button-and-refactoring

tmp-1-4-button-and-refactoring