Extract common parts of wxData{In,Out}putStream in a common base class.

No real changes, just put BigEndianOrdered() and SetConv() methods and the
corresponding fields in a common wxDataStreamBase class instead of duplicating
them in wxDataInputStream and wxDataOutputStream.

This will make it simpler to add more features common to both classes in the
future, see #10625.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73933 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
No real changes, just rename double variables to "d".

Don't use "i" or "f" for double variable names, this is confusing, especially
when we do it inconsistently.

See #10625.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73934 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
No changes, just a small optimization in DataStreamTestCase.

Don't create streams on the heap completely unnecessarily, just allocate them
on the stack. This makes the code shorter, safer and slightly more efficient.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73935 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Test wxDataStream floating point methods in big endian format too.

Added a hack to test float/double reading/writing using
wxDataInputStream/wxDataOutputStream to the test case using big endian
extended float format too.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73936 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Minor wording fixes in wxDataStream classes documentation.

Mostly just s/amount/number/

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73937 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Add IEEE 754 single/double precision support to wxDataStream classes.

Allow to optionally raed/write float/double values in IEEE 754 single/double
precision formats, respectively, instead of always using the extended
precision format for both of them.

This makes the code more flexible, allowing for better interoperability with
the other programs, and also allows to implement floating point functions in
these classes even when wxUSE_APPLE_IEEE is turned off (as can be the case
because of the licencing concerns for the code in extended.c).

Closes #10625.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73938 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775