Add some oligo anaysis features

This issue is a request from FCP.

Find in the attachment the program that has the features to be implemented.

The following features present in this program should be implemented in UGENE (these features are for a nucleotide sequence):

1. Calculation of the "MW" (i.e. Molecular Weight)
2. Calculation of the "Molar extinction coef."
3. Calculation of number of "GC" in the sequence
4. Calculation of the maximum primer melting temperature (i.e. "Tm"), based on:

• The sequence
• "Salt cc" (this value is input manually by user)
• "Primers cc" (this value is input manually by user)