ENH: Add batteries-included index and DataFrame generators to tm
``` python
In [1]: from pandas.util.testing import makeCustomDataframe as mkdf
   ...:   mkdf(5,3)
Out[1]: 
C0      C_l0_g0 C_l0_g1 C_l0_g2
R0                             
R_l0_g0    R0C0    R0C1    R0C2
R_l0_g1    R1C0    R1C1    R1C2
R_l0_g2    R2C0    R2C1    R2C2
R_l0_g3    R3C0    R3C1    R3C2
R_l0_g4    R4C0    R4C1    R4C2

In [2]: from random import randint
In [2]: mkdf(5,3,data_gen_f=lambda r,c:randint(1,100))
Out[9]: 
C0       C_l0_g0  C_l0_g1  C_l0_g2
R0                                
R_l0_g0       38        9       64
R_l0_g1       42       45       94
R_l0_g2       15       94       16
R_l0_g3       80       39       33
R_l0_g4       94       30       63

In [3]: mkdf(5,3,c_idx_names=False,r_idx_names=False,
   ...:                              r_idx_type="dt",c_idx_type="u")
Out[3]: 
           ס4ןדםבדפגמ ץי4ףצ8י1נ2 3מקףיזשד4ר
2000-01-03       R0C0       R0C1       R0C2
2000-01-04       R1C0       R1C1       R1C2
2000-01-05       R2C0       R2C1       R2C2
2000-01-06       R3C0       R3C1       R3C2
2000-01-07       R4C0       R4C1       R4C2

In [4]: mkdf(5,3,r_idx_nlevels=2,r_ndupe_l=[2])
Out[4]: 
C0              C_l0_g0 C_l0_g1 C_l0_g2
R0      R1                             
R_l0_g0 R_l1_g0    R0C0    R0C1    R0C2
        R_l1_g1    R1C0    R1C1    R1C2
R_l0_g1 R_l1_g2    R2C0    R2C1    R2C2
        R_l1_g3    R3C0    R3C1    R3C2
R_l0_g2 R_l1_g4    R4C0    R4C1    R4C2

In [5]: mkdf(5,3,r_idx_nlevels=4,
   ...:                              r_idx_names=["FEE","FI","FO","FAM"],
   ...:                              c_idx_nlevels=2)
Out[5]: 
C0                              C_l0_g0 C_l0_g1 C_l0_g2
C1                              C_l1_g0 C_l1_g1 C_l1_g2
FEE     FI      FO      FAM                            
R_l0_g0 R_l1_g0 R_l2_g0 R_l3_g0    R0C0    R0C1    R0C2
R_l0_g1 R_l1_g1 R_l2_g1 R_l3_g1    R1C0    R1C1    R1C2
R_l0_g2 R_l1_g2 R_l2_g2 R_l3_g2    R2C0    R2C1    R2C2
R_l0_g3 R_l1_g3 R_l2_g3 R_l3_g3    R3C0    R3C1    R3C2
R_l0_g4 R_l1_g4 R_l2_g4 R_l3_g4    R4C0    R4C1    R4C2

```
