Fix compilation of es/EmbeddedObjects.lyx

Since a2e8cb75, \lstlistingname is localized. Redefining it
in the preamble is not necessary and in fact since f4dd0ba5
leads to a compilation error.
Fix dataloss for align env inside math

The math parser aborts with an error message on \begin{align} and
\begin{align*} if this is not the hull inset. This is now fixed, however
this is not complete support for these two environments (the GUI does not
respect the numbering). It is only the minimal fix that ensures that no data
loss occurs for documents imported by tex2lyx.
EmbeddedObjects.lyx: describe the usage of \mbox