auto expand log scale to include at least two major ticks
Use a different axes_pad parameter for log scale.

This fixes problems with user-specified minimum values that
was not being applied correctly earlier.
Merge branch 'develop' into ticket/13528
integrate sync-build into setup.py
Having SAGE_LIB point to SAGE_SRC is actually never useful, removed
automatically doctest sage_setup
make use of the new SAGE_LIB
remove annoying warning from sage -ba
re-enable out-of-tree cythonize
Merge branch 'develop' into t/13528/ticket/13528
merge ticket 13422 on to 13528
Reintroduce the changes of this ticket 13528

This is now rebased on to 13422.
forgot to pass the axes_pad parameter.

Also added some doctests and modified existing ones.
small changes to initial sage_setup package
Merge branch 'u/ppurka/ticket/13528' of ssh://trac.sagemath.org/sage into ticket/13528
fix latex build: \text -> \mathrm
fix _ in latex of axes_pad
Trac #16431: sync-build is broken

`sage -sync-build` doesn't understand wildcards, so it deletes a bunch
of correctly-installed `sage.symbolic` modules.

Really, the whole concept is broken. We should at the very least record
what is being installed instead of trying to guess it in sync-build.
Even better, make it part of the build process.

There is quite a lot of setup code, none of which is doctested. And,
therefore, broken. As this ticket shows. I've started to move setup code
into a `sage_setup` package that is installed with Sage and can be
doctested in the usual manner.

Also:
* Having `SAGE_LIB` point to `SAGE_SRC` is actually never useful,
removed.
* re-enable out-of-tree cythonize

URL: http://trac.sagemath.org/16431
Reported by: vbraun
Ticket author(s): Volker Braun
Reviewer(s): R. Andrew Ohana
Trac #13528: ymin is not respected in logarithmic plots

See this [https://groups.google.com/forum/?fromgroups=#!topic/sage-
devel/OnhVtHXgdls sage-devel thread]

1. I've been experiencing some problems with logarithmic scale plots
since the 'semilogy', 'semilogx' and 'loglog' options had been added.
For example, when I use the 'semilogy' plot, I can adjust the 'ymax'
value, but not 'ymin' value. 'ymin' is always set automatically, and not
always correctly.
2.  I have also noticed that if I have several curves on a single
'semilogy' plot, the lower Y limit is set according the minimum value of
the FIRST curve. '''Can not reproduce this case -basu.'''

Example showing weird behavior on decreasing `ymin` to `1e3`, `1e4`,
etc., but exhibiting correct behavior on changing `ymax`.
{{{
dPhi = 6.02e10 * x**(2.481) * exp(-x / 1.205)
plot(dPhi, 0, 20, scale='semilogy', figsize=(5,4), ymin=1e7, ymax=1e11,
xmin=0, xmax=20, frame=True)
}}}

----

Apply to `devel/sage`:
1. #13422
2. [attachment:trac_13528-rebase.patch ]

URL: http://trac.sagemath.org/13528
Reported by: ppurka
Ticket author(s): Punarbasu Purkayastha
Reviewer(s): Karl-Dieter Crisman