Fix pool table column cut issue

[polartar]

Fixes #98.

Changes proposed in this pull request:

• Created classes for different window sizes
• Fixed table column issue in the Reward pool table
• Fixed table column issue in the Create pool table

[bullishgopher]

1. Except Assets column, others should be right-aligned
2. If the screen size is smaller than 980px, the table headers are broken

[polartar]

@gokhanmelma While merging the PR, some columns were removed. That's why the header is broken. I have just fixed it