"SEARCH" is renamed to "SEARCH LIBRARY"

#### Purpose

1. Change search text hint from `SEARCH` to `SEARCH LIBRARY`.
2. Change this label normal font color to `#AAAAAA`.

#### Modifications

##### Before
![image](https://cloud.githubusercontent.com/assets/8158551/5259937/cc51468a-7a10-11e4-9c30-6c582d283897.png)

##### After

![image](https://cloud.githubusercontent.com/assets/8158551/5259991/9712d992-7a11-11e4-9568-6516c35f6274.png)

#### Additional references

[MAGN-5571](http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-5571).

#### Reviewers

@ramramps, please, take a look.
@Benglin, FYI.