Update endians.nim

adds swapEndian16 function
Adds example to locals() docstring.
Adds docstring to rstgen.defaultConfig.
Update os.nim

added file/dirExists synonyms for existsFile/dir
Added --noBabelPath override.
Define $ operator for TRune
Define $ operator for TRune
Remove assert in asyncio which causes problems.

This assert keeps failing occassionally in nimbuild causing it to crash.
According to logic it shouldn't, but perhaps the socket's writeable
status changes.
Fixes #594

This was already partially fixed, ``expandTilde`` was the missing piece
from perfection.
httpclient: strip trailing whitespace from headers.

- we can do that according to the RFC.
- fixes #783
Merge pull request #776 from gradha/pr_docs

Docstrings
Removes generated .dot file uploaded by mistake.
Merge pull request #791 from gradha/pr_removes_generated_file

Removes generated .dot file uploaded by mistake.
Merge pull request #788 from zielmicha/httpclient-fix

httpclient: strip trailing whitespace from headers.
case consistency improvements
Koch now uses PATH/nimrod correctly
Add info about twitter and bootstrapping from github to website.
new vm: bugfix
bugfix: renderer supports 'ptr' etc. as type constraint
Rename C sources dir to c_code.