* when saving to csv without transposing the last dimension, create a series directly instead of going through a dataframe
* added header to non transposed csv
* actually check the result in savecsv test and added test with transpose=True (default)
simplified as_dataframe() and added axes_labels property
make it more obvious that we are not messing with the original name
* changed as_dataframe and as_series methods to properties (.df and .series respectively)
* changed save_XXX functions to to_XXX methods (like Pandas) and simplify them
* renamed XXX_h5 to XXX_hdf to stay close to Pandas
* kill SaveMatrices, LoadMatrix, ListMatrices
* kill ToCsv, Collapse and ToAv
* improved to_excel docstring
cleanup df_aslarray
fixed df_as_larray
added test for read_csv wh 2d array
renamed test.csv to test5d.csv
added test for 3d array