Support inline input (pre-edit,surrounding-text) when using input-method, Fix #1071

Fix https://github.com/linuxmint/Cinnamon/issues/1071.

Please also merge : https://github.com/linuxmint/muffin/pull/65 but this merge can works alone

These images are state of when I type "てすと(tesuto)" into searchEntry.

Before.
![ibus](https://f.cloud.github.com/assets/1858413/99656/1c481412-67a7-11e2-9d52-578f02bceea2.png)

If merge this;
![ibus0](https://f.cloud.github.com/assets/1858413/126239/9c7fedda-6f45-11e2-8f2a-41a1396dce73.png)

If merge https://github.com/linuxmint/muffin/pull/65 with muffin;
![ibus2](https://f.cloud.github.com/assets/1858413/99657/2f5054fc-67a7-11e2-97bd-291244ea2752.png)

If merge https://github.com/linuxmint/muffin/pull/65 with muffin , and merge this;
![ibus3](https://f.cloud.github.com/assets/1858413/99659/3d6b78a0-67a7-11e2-901c-3f1191ea77d6.png)