Add draft of a README that provides an overview.
Better explanation of annotated source generation.
Remove Documentation section.

I think it would be better to have a sectio with links, probably earlier
in the README or throughout it. For example, there already is a link to
the documentation.
Fix link to helloworld-app.
Note which samples are services and which are apps.
Use the hyphenated form of the pedestal components.
Highlight which components the samples use in the README.
Merge pull request #29 from heyLu/gentle-introduction

Provide a more gentle introduction to the samples.