org-e-latex: Change tables attributes and implement matrix support
* contrib/lisp/org-e-latex.el (org-e-latex-table-matrix-macros,
org-e-latex-default-table-mode): New variables.
(org-e-latex-tables-verbatim): Removed variable.
(org-e-latex-tables-booktabs): Update docstring.
(org-e-latex--align-string, org-e-latex--org-table,
org-e-latex--table.el-table): Rename functions from, respectively
`org-e-latex-table--align-string', `org-e-latex-table--org-table' and
`org-e-latex-table--table.el-table'. Use new attributes.
(org-e-latex-table,org-e-latex-table-row): Use new attributes.
(org-e-latex--math-table): New function.