Adding a new constructor for InternedString that takes a 64bit signed integer and convert it to string.

The implementation uses a static map from numbers to the InternedStrings for quick instantiation.
Also it results on the same InternedString created if passing the corresponding numeric string.
Using it in SceneCache for quickly finding the sample entry names.
Making sure the g_numbers map is initialized before any static numeric InternedString is instantiated.
sceneInterface:link has now been broken down into sceneInterface:root, sceneInterface:fileName and sceneInterface:time in the LinkedScene, although the mechanism for writing a retimed link remains the same
changed the names of the link/time attributes in the LinkedScene
totally disabled time remapping for legacy linked scenes, plus fixed a typo/bug
fixed first time write bug
Made sceneInterface:link.time readable from all points in a LinkedScene Hierarchy
Storing the sampleTimesIndex as a IndexedIO::Directory as opposed to a double entry to force preloading that info once at open time.
Building full scene paths in a better way with no double /
Merge pull request #43 from valeriebernard/sceneShapeFullPathNames

Building full scene paths in a better way with no double /
Scene shape components can now be framed, in a similar way as the proceduralHolder. Reading component bound and transform directly from the scene interface.
Bug fix: SceneShapeInterface::componentBound returns a Box3d
Using fullPathName when querying the component bounds.
Merge pull request #42 from ldmoser/numericInternedString

Adding a new constructor for InternedString that takes a 64bit signed integer and convert it to string.
Adding includeChildren parameter to SceneInterface::hasTag().

That also enabled fixing the LinkedScene unit test for tags.
Merge pull request #41 from valeriebernard/sceneShapeFramingComponents

Scene shape components can now be framed in the view port, in a similar way as the proceduralHolder
Merge pull request #44 from ldmoser/optimSamplesSceneCache

Changing representation of sampleTimesIndex in the SceneCache
Merge pull request #45 from ldmoser/includeChildrenInHasTag

Adding includeChildren parameter to SceneInterface::hasTag().
added unit test for nested time remapping
updated linked scene code