Two RTL Fixups in Studio and CAPA problems

Description

1. Fixed RTL icon margin in the studio


Before:

![image](https://cloud.githubusercontent.com/assets/645156/6168009/b81060e2-b2c9-11e4-814c-edfebd6bf59d.png)

After:

![image](https://cloud.githubusercontent.com/assets/645156/6168025/f35d7aa4-b2c9-11e4-8df2-1bc8d5b6dc2b.png)

Cherry picked from our fork (https://github.com/Edraak/edx-platform/pull/64).


2. Make math equation fields always LTR in CAPA problems


This one is clear. Since all the equation input is in English, the field should be always LTR.

Cherry picked from our fork (https://github.com/Edraak/edx-platform/pull/74).

Assignee

Alisan Tang

Reporter

Edx Admin [Administrator]

Contributor Name

Omar Al-Ithawi

Repo

edx/edx-platform

Customer

Epic Link

None

OSCM Assignee

None

Platform Map Area (Levels 1 & 2)

None

Platform Map Area (Levels 3 & 4)

None

Story Points

0.5

Priority

Unset
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