Update system_requirements.md

Under system requirements there is a typo at
"You'll find these requirements listed below, broek ndown into their distinct groups."
I changed the above line to
"You'll find these requirements listed below, break down into their distinct groups."
Update system_requirements.md

Under system requirements there is a typo at
"You'll find these requirements listed below, break down into their distinct groups."
I changed the above line to
"You'll find these requirements listed below, broken down into their distinct groups."
Update gantry_core_concepts.md

Change:

"An important new features in Gantry 4 is the ability to add and compile LESS files"

to

"An important new feature in Gantry 4 is the ability to add and compile LESS files"
Merge pull request #73 from simmonsr/patch-1

Update gantry_core_concepts.md
Update layouts.md
Merge pull request #74 from simmonsr/patch-2

Update layouts.md
Merge pull request #71 from deepu9/patch-1

Update system_requirements.md
Fix typo in custom_stylesheet.md

Changed 'One of the way is by...' to 'One way is by...'
Another option is 'One of the ways...', but I opted for less words
Merge pull request #76 from clouder/patch-1

Fix typo in custom_stylesheet.md
Module Addition Note