Merge pull request #91 from edgy360/master

Fix #89 (Missing quotation marks for device name)
fixed button sizes Fixed #90
Merge pull request #93 from Astro03/master

fixed button sizes Fixed #90
Update AppiumEngine.cs

Removed ERROR string on std-err input so not to confuse users.
fixed #88
Rename README image filenames to fix documentation on Appium.io.