New tag names are not sanitized

• Create a new score.

• Go to File > Info... and a a new tag with this name:

  My new "tag"
  

• Click OK.

• Save the score and close it.

• Try to open the score.

Result: we can't open it:

Cannot read file /path/to/score.mscx:
bad format

If we extract the content of score.mscx and open score.mscx, we see that the new tag name is not sanitized:

<metaTag name="My new "tag"">content</metaTag>

There are other characters that cause problems. Example:

My new <tag>

In the file score.mscx:

<metaTag name="My new <tag>">content</metaTag>

Config: MuseScore a7dab0a on Xubuntu 14.10.