Fix draft request parameter

require php 7.1

Merge pull request eversign#21 from Nathanw/master

Added custom requester properties.

Merge pull request eversign#20 from dtolstyi/master

Fixed 'expression is not allowed as class constant value' error with PHP5.5 (fixes eversign#19)

fix eversign#18 - multipart upload error message not displayed correctly

add info request

add .idea to gitignore

Merge pull request eversign#16 from devbazilio/add_method_for_updatin…

…g_doc

Updates for Client, Document and Signer models

Merge pull request eversign#15 from devbazilio/fix_checkbox

Fix initialisation of CheckBox field

check for json_last_error() - fix eversign#13