Use wp_is_writable wherever is_writable was used.
Bump required version to 3.6.0
Merge branch 'master' into wp-is-writable-function-371

Conflicts:
	functions/core.php
Fixes an issue on servers which only allow a single session per client

Signed-off-by: Paul de Wouters <paul@hmn.md>
Merge pull request #446 from humanmade/close-php-session-446

Issues on servers which only allow a single session per client
Send max execution time to intercom

Signed-off-by: Paul de Wouters <paul@hmn.md>
Clean up readme
Update UTM
Merge branch 'master' into wp-is-writable-function-371

Signed-off-by: Paul de Wouters <paul@hmn.md>

Conflicts:
	backupwordpress.php
Merge pull request #427 from humanmade/pass-timeout-intercom

Pass PHP timeout setting to Intercom
Merge pull request #371 from humanmade/wp-is-writable-function-371

Use wp_is_writable to check if backups dir is writable
Merge branch 'master' into pass-display-name

Signed-off-by: Paul de Wouters <paul@hmn.md>

Conflicts:
	classes/class-requirements.php