Bug 2147 - JSON does not properly encode multiline string

* added newline and return characters to escape list
* updated tests

Change-Id: I48cd418b1633de12e80bdab0b7c7bc91113dbf6d
Signed-off-by: Jan Hajnar <jhajnar@cisco.com>
(cherry picked from commit e6c3a206a204de77c70df1c0940a088493401749)
Merge "Bug 2147 - JSON does not properly encode multiline string" into stable/helium