More information for setting up database.yml

Added 2 more steps in the Setup of database.yml. These are to uncomment the "development:" and "test:" part of the file.
Install all database components at once
Add commands for setting up database users in Postgres
Link the database.yml file instead of copying it

It is harder to ignore changes to the default database.yml.postgresql
file if the file is a link instead of a copy.
Update GnuLinux installation instructions for Ubuntu 14.04
Switch ruby-execjs for libv8-dev

libv8-dev is all that is needed and ruby-execjs included other things
that will be handled by bundler.
Fix a typo
Configure libv8 in the Gemfile instead of installing it separately
Testing out the internal wiki links
Merge pull request #38 from ferrous26/master

Update installation instructions for Ubuntu 14.04
Merge pull request #40 from oneohtrix/master

add howto for setting up devenv
Merge pull request #36 from gillianchesnais/patch-1

More information for setting up database.yml
Copy the database.yml instead of linking it
Merge branch 'master' of github.com:MarkUsProject/Wiki
Merge pull request #41 from ferrous26/master

Copy the database.yml instead of linking it
Current Ubuntu versions install Postgres 9.3.4, so OS X should do so too
Remove duplicated instruction from pg setup
Update RVM and libsvn-ruby setup instructions
Update Linux install instructions to not mention Ruby 1.8 anymore
Merge pull request #44 from ferrous26/drop-1.8

Update Linux install instructions to not mention Ruby 1.8 anymore