Merge search path for include & import from backend branch. And add corresponding support for <include> to BBv2 quickbook tool. Remove obsolete quickbook.xml file. (fixes #1263)

[SVN r40469]

tools/build

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-Subproject commit 7ce0854865ace48b15a6bb4b468d79bfa6e5b7bb
+Subproject commit 9a6dc34fa1244993e70247a870792c65eec5de35

tools/quickbook

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-Subproject commit 59d2a41f26c468f67b0c881b43700e83311ecffb
+Subproject commit fbc4fea44c39cc4e2172692f2f43b58b83547b87