Multiple improvements to build process

Restructure and document retroshare.pri variables and helper functions
Link sqlite statically like other libraries on Android
qmake has multiple win32-* specs match them correctly
Move a buch of generic thing to retroshare.pri instead of having them replocated
  accross project specific .pro
Fix retroshare-gui too many symbols exported on windows liking error by adding
  QMAKE_LFLAGS+=-Wl,--exclude-libs,ALL
Rename retroshare-gui/src/util/win32.h because the name is too prone to
  confusion and build conflicts
libreasapi avoid usage of cretar_prl link_prl that seems unreliable on some
  platforms
libreasapi rename LIBRESAPI_QT to more understendable LIBRESAPI_SETTINGS
Use use_*.pri instead of copy pasting error prone qmake snippets around
Expose bitdht option to retroshare.pri
Add RS_THREAD_LIB qmake variable for better crossplatform support
Move debug and profiling generic options to retroshare.pri (avoid copy/pasting)
Remove Qt script module in qmake as it is not available anymore

retroshare-android-service/src/retroshare-android-service.pro

@@ -11,43 +11,8 @@ android-*:CONFIG += dll
 android-*:TEMPLATE = lib
 !android-*:TEMPLATE = app
 
-DEPENDPATH *= ../../libresapi/src
-INCLUDEPATH *= ../../libresapi/src
-PRE_TARGETDEPS *= ../../libresapi/src/lib/libresapi.a
-LIBS *= ../../libresapi/src/lib/libresapi.a
+!include("../../libresapi/src/use_libresapi.pri"):error("Including")
 
-DEPENDPATH *= ../../libretroshare/src
-INCLUDEPATH *= ../../libretroshare/src
-PRE_TARGETDEPS *= ../../libretroshare/src/lib/libretroshare.a
-LIBS *= ../../libretroshare/src/lib/libretroshare.a
-
-win32 {
-        OBJECTS_DIR = temp/obj
-
-        LIBS_DIR = $$PWD/../../libs/lib
-        LIBS += $$OUT_PWD/../../libretroshare/src/lib/libretroshare.a
-        LIBS += $$OUT_PWD/../../openpgpsdk/src/lib/libops.a
-
-        for(lib, LIB_DIR):LIBS += -L"$$lib"
-        for(bin, BIN_DIR):LIBS += -L"$$bin"
-
-
-        LIBS += -lssl -lcrypto -lpthread -lminiupnpc -lz -lws2_32
-        LIBS += -luuid -lole32 -liphlpapi -lcrypt32 -lgdi32
-        LIBS += -lwinmm
-
-        DEFINES *= WINDOWS_SYS WIN32_LEAN_AND_MEAN _USE_32BIT_TIME_T
-
-        DEPENDPATH += . $$INC_DIR
-        INCLUDEPATH += . $$INC_DIR
-
-        greaterThan(QT_MAJOR_VERSION, 4) {
-                # Qt 5
-                RC_INCLUDEPATH += $$_PRO_FILE_PWD_/../../libretroshare/src
-        } else {
-                # Qt 4
-                QMAKE_RC += --include-dir=$$_PRO_FILE_PWD_/../../libretroshare/src
-        }
-}
+!include("../../libretroshare/src/use_libretroshare.pri"):error("Including")
 
 SOURCES += service.cpp