Fix link to roadmap on site home page

https://github.com/Araq/Nimrod/wiki/Feature-Matrix does not exist, while https://github.com/Araq/Nimrod/wiki/Roadmap does.
Merge pull request #1370 from roryokane/patch-1

Fix link to roadmap on site home page
Mentions countLines() may return unexpected values.
Homogenizes docstrings for strutils module.

This mostly involves separating the short description string from the
full description block, capitalizing it, and adding any worthwhile
hyperlinks to other symbols.
Merge pull request #1372 from gradha/pr_strutils_docstrings

Improvements to strutils docstrings
sequtils: Correct documentation for keepIf proc
sequtils: Complete mapIt documentation example
Update nimrod.ini
Merge pull request #1378 from sjakobi/patch-2

sequtils: Complete mapIt documentation example
Merge pull request #1377 from sjakobi/patch-1

sequtils: Correct documentation for keepIf proc
Hyperlinks echo variants with noSideEffect pragma. Refs #1379.
Fixes #1219.
Remove unnecessary import
Fixes #1065.
typo fix
replaced var with let in system.nim

Nitpicking.
Merge pull request #1394 from PavelVozenilek/patch-2

typo fix
Merge pull request #1396 from PavelVozenilek/patch-5

replaced few var with let in system.nim
fixes #1395
fixes #1391