Added doc for new form csrf method

Signed-off-by: Derek Myers <arcticpro@gmail.com>
Change CSRF in security docs to use new form csrf method

Signed-off-by: Derek Myers <arcticpro@gmail.com>
updated asset docs to include the new inline feature
fixed typo in observer docs
explained the use of DB::expr() when using literals in a join
Updates develop branch version number.
is_frozen() doesn't exists, corrected to frozen()
Merge pull request #571 from Art4/1.7/develop

is_frozen() doesn't exists, corrected to frozen()
documented Input::patch()
second parameter of Config::save() is not optional
clarified the difference between PUT and PATCH;added a note that all HTTP methods are supported
Added get_path() method, fixed typo
Merge pull request #572 from Art4/patch-1

Added get_path() method, fixed typo
Merge pull request #566 from dmyers/feature/form-csrf

Added doc for new form csrf method
documented Arr::insert_assoc()
fix classes/cli.html
Merge pull request #575 from shinagaki/fixed_cli

fix classes/cli.html
documented lazy load get() conditions
Document added extension() method
Merge pull request #576 from propcom/1.7/develop

Document added extension() method