Updates to language overview:
Updates to language overview:

- Divided up some sections.
- Added text and examples to sequence and iterator sections.
- Cleaned up beginning.  This text is now just a placeholder.  It needs
  improvement.
- I addressed some of Steve's comments.
- I deleted part of the statement and expression examples.  They are no
long entire programs.


git-svn-id: 88467cb1fb04b8a755be7e1ee1026be4190196ef@8296 3a8e244f-b0f2-452b-bcba-4c88e055c3ca

CoryMcCartan/chapel,sungeunchoi/chapel,sungeunchoi/chapel,sungeunchoi/chapel,hildeth/chapel,chizarlicious/chapel,CoryMcCartan/chapel,sungeunchoi/chapel,chizarlicious/chapel,hildeth/chapel,hildeth/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,hildeth/chapel,chizarlicious/chapel,hildeth/chapel,chizarlicious/chapel,chizarlicious/chapel,hildeth/chapel,chizarlicious/chapel,hildeth/chapel,sungeunchoi/chapel,sungeunchoi/chapel,CoryMcCartan/chapel,sungeunchoi/chapel,sungeunchoi/chapel,chizarlicious/chapel