Remove the extra T2DMap default constructor.

T2DMap currently has two default constructors, remove one.
Deleting the host will make pH a dangling pointer, so remove it from mTabMap first.
Remove Host's default constructor, which isn't used.
Remove QT_NO_STL, it's not properly documented.
Merge pull request #13 from ahmedcharles/host_fix

Deleting the host will make pH a dangling pointer, so remove it from mTabMap first.
Merge pull request #8 from ahmedcharles/t2dmap

Remove the T2DMap default constructor.
Merge pull request #11 from ahmedcharles/host

Remove Host's default constructor, which isn't used.
Merge pull request #21 from ahmedcharles/qt_no_stl

Remove QT_NO_STL, it's not properly documented.