Start developer documentation
Fix bounds error in forward-i-search
Bind remaining control characters in the search keymap

New functionality:
  ^L clears the display
  ^N and ^P iterate through the next or previous result
  ^G and ESC-ESC cancel search mode
  ^W erases the previous word to whitespace
Add a REPL manual section: "Interacting with Julia"
Merge pull request #6673 from JuliaLang/teh/devdocs

Start developer documentation
Merge pull request #6697 from mbauman/doc-repl

RFC: Add a REPL manual section: "Interacting with Julia"
Merge pull request #6682 from mbauman/search-bounds

Fix #6671: Check search bounds and bind missing control characters in i-search modes
Clean up temp file litter
Replace zero(T) with 0 in sparse matrix code.
Merge pull request #6705 from tkelman/patch-4

Clean up temp file litter
readdlm improvements:

- speed up reading of large files if dimensions are known
- prefer doing two passes when offset storage may take too much ram
- moved readdlm into a module to contain symbols