Merge files Text{,2,3}.cpp

This is done at the end of the release cycle to avoid backporting issues.

The goal is to simplify development, since it was difficult to guess
in which file a given method could be found.

There is some effect on compilation time, but it is not too bad:

* before merge

  lapinot: time make Text.o Text3.o Text2.o
    CXX      Text.o
    CXX      Text3.o
    CXX      Text2.o

  real	0m32,504s
  user	0m31,027s
  sys	0m1,446s
  lapinot: rm Text*.o
  lapinot: time make -j8 Text.o Text3.o Text2.o
    CXX      Text.o
    CXX      Text3.o
    CXX      Text2.o

  real	0m21,282s
  user	0m32,661s
  sys	0m1,424s

* after merge

  lapinot: time make Text.o
    CXX      Text.o

  real	0m26,731s
  user	0m25,706s
  sys	0m1,020s

src/Makefile.am

@@ -177,8 +177,6 @@ SOURCEFILESCORE = \
 	TexRow.cpp \
 	texstream.cpp \
 	Text.cpp \
-	Text2.cpp \
-	Text3.cpp \
 	TextClass.cpp \
 	TextMetrics.cpp \
 	TocBackend.cpp \

src/insets/InsetFloat.cpp

@@ -866,7 +866,7 @@ void InsetFloat::docbook(XMLStream & xs, OutputParams const & runparams) const
 
 bool InsetFloat::insetAllowed(InsetCode code) const
 {
-	// The case that code == FLOAT_CODE is handled in Text3.cpp,
+	// The case that code == FLOAT_CODE is handled in Text.cpp,
 	// because we need to know what type of float is meant.
 	switch(code) {
 	case WRAP_CODE: