Fix wiki links

Seems to have broken with GitHub's relative link change https://github.com/blog/1395-relative-links-in-markup-files
Merge pull request #263 from benjaminoakes/patch-1

Fix wiki links

Github's new way of handling relative links broke some of the
links in the readme file.
Prevent side effect of wildignore

Certain wildignore values prevented the various logs from being
viewable.

Fixes #249
Generate helptags independently from user settings

The wildignore setting affects the behaviour of the `= shorthand, so
this changeset replaces the last remaining use of such construct with a
call to exec.
ignore netrwhist file
Merge pull request #271 from adjohnson916/master

Ignore .netrwhist" until rtp ordering is fixed

Because vundle modifies the directory that appears first in the rtp, some files that vim generates in the first directory in rtp end up in the vundle directory. This is a known issue in vundle but until it is resolved, ignore .netrwhhist when found in the vundle directory.
Check for leading/trailing spaces in bundle specs

Warn the user when a leading or trailing space is found in one the
bundle specs they have configured using the Bundle command.
Show error in installer if helptags fails

Failures in :helptags commands for individual bundles were logged but
the error were not propagated to the installer.
Readme and doc clarification about local git repos
make the doc/vundle.txt the same as README.md
Merge pull request #319 from grantbow/master

make the doc/vundle.txt the same as README.md
Bundler link update