Fix string construction of submit button in Flag

Summary: Fixes T3674.

Test Plan: Clicked "flag for later"; checked error log.

Reviewers: btrahan, chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T3674

Differential Revision: https://secure.phabricator.com/D6669
Minor, fix Paste SQL patch for databases with all warnings turned on.

This column has no default value and throws if you have maximum warnings activated:

  EXCEPTION: (AphrontQueryException) #1364: Field 'commentVersion' doesn't have a default value...

Auditors: btrahan
Handle "multipart/form-data" correctly even if we get the data

Summary: Fixes T3673. Supposedly we won't get any data in this case, but it seems we sometimes do. See discussion in task.

Test Plan: Used `var_dump()`, etc., to verify we short circuit out of "multipart/form-data" posts regardless of the presence of input data.

Reviewers: nmalcolm, btrahan

Reviewed By: nmalcolm

CC: aran

Maniphest Tasks: T3673

Differential Revision: https://secure.phabricator.com/D6670
Line highlighting for pastes

Summary:
Add the ability to select singular and multiple lines in paste to highlight.
This is related to T3627

Test Plan: Create a paste, select one or more lines.

Reviewers: epriestley, tberman

Reviewed By: epriestley

CC: aran, chad

Maniphest Tasks: T3627

Differential Revision: https://secure.phabricator.com/D6668