Fix capitalization in README

Tweak to readme.

Update Contrib README with small nuance about Delete

Deleting an entity will delete only by a specified key property and not by
any specified parameter

Removed text about connections having to be open, which is not true any longer.

Adding section about SQLite limitation

More information at #300

Better Dapper.Contrib README

- Added an example for the [Table] attribute which was missing.
- Additionally separated things onto separate lines for better
readablility
- Better headings

Brackets around property names in Update & Delete

Modified Update & Delete method to be consistent with Insert by adding brackets around property names

SO30435185; make it clearer if the caller is passing an array (etc) when they should be passing a single object

Conflicts:
	Dapper NET40/SqlMapper.cs