[FIX] _enoughSpaceBelow + Avoids duplicate calls of functions

• Changed the _enoughSpaceBelow _enoughSpace (checking both
possibilities targeting to open the drop-down menu above or below)
• Avoid duplicate calls of functions (as _openDropdown and
_enoughSpaceBelow)
Merge pull request #135 from acemir/version-1.1

[FIX] _enoughSpaceBelow + Avoids duplicate calls of functions