Allow rtp paths with spaces on Windows

Suggested by @ikurcubic
Merge pull request #454 from vaibhavsagar/patch-1

Allow rtp paths with spaces on Windows

Fixes #451
Fixes #453
Clarified comment for non GitHub example in Configure bundles
Bump version to 0.10.1
Merge branch 'master' into next
change function g:shellesc_cd into vundle#installer#shellesc_cd
Limit default rtp rearrangement

Rearranging rtp so that **all** default directories appear first has the
undesired side effect of not allowing plugins to override default syntax
files.

This changeset limits the rearrangement of the rtp to simply making sure
the first directory in the default runtimepath appears first in also in
the runtimepath after Vundle has finished manipulating it.

This should keep the original bugs fixed and should eliminate the
aforementioned undesired side effect.

Fixes #430
Fixes #456
Bump version to 0.10.2
Correct new version in changelog.md
Change reference of `Bundle` to `Plugin` in the docs
add command to visit homepage of a bundle

The open-browser plugin is used if it is available.  Else some simple tests
are made and the URL of the bundle is opened via the system's default
procedure.

TODO: test on different operating systems