added custom_word_frequency_dataframe function to create dataframe like word_freq_df but with custom words as input - also adjusted plotting function to allow it to plot arbitrary dataframes, e.g. dataframe created with custom_word_frequency_dataframe function
added custom_word_frequency_dataframe function to create dataframe like word_freq_df but with custom words as input - also adjusted plotting function to allow it to plot arbitrary dataframes, e.g. dataframe created with custom_word_frequency_dataframe function

ddandur/Twords