Fix parsing of JS imports from JS files

If a .js file had an import of another .js file itself, like so:

    .import "otherFile.js" as Blah

then the import scanner would keep the quotes and store

    "\"otherFile.js\""

in the JSON as opposed to

    "otherFile.js"

This is fixed by making use of the same code for extracting the .import
statements from JS files that is also used by the engine itself.

Additionally this fixes the use of comments in .import lines (and other
whitespace characters not producing tokens).

Change-Id: I4dd4a5217308f6fc93b6b148cd8e13392f97d2a6
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Fix crash when loading QML that tries to set non-existent group properties

This happens when trying to search for implicit component definitions,
which only makes sense if we have a property cache.

Task-number: QTBUG-38466
Change-Id: I788159453efc24bcda1b9709a1933b49fd54d6a7
Reviewed-by: Liang Qi <liang.qi@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
V4 regalloc: fix register spill choice under high pressure.

When a register is needed for an input parameter of an operation, and
all registers are already in use, do not select a register for spilling
when it is also used in the current operation.

Task-number: QTBUG-38451
Change-Id: I4a8f28cbaadce2dbb9d0c450ccac0ed572936c24
Reviewed-by: Albert Astals Cid <albert.astals@canonical.com>
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Getting the render window of an offscreen window

When using a QQuickWidget, the QQuickWindow is hidden and the contents
are displayed in another window. Some components need to query the actual
window, e.g. when positioning a popup.

Task-number: QTBUG-38116
Change-Id: I34452be2179ccc9e216e4d89264dc700e0cf42a0
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>