Improved the prettiness of the print methods.

[LTLA]

from iranges import IRanges
X = IRanges(start=[1, 2, 3, 4], width=[10, 20, 30, 40])
print(X)
## IRanges object with 4 ranges and 0 metadata columns
##         start       end     width
##     <ndarray> <ndarray> <ndarray>
## [0]         1        11        10
## [1]         2        22        20
## [2]         3        33        30
## [3]         4        44        40

import numpy as np
from biocframe import BiocFrame
Y = X.set_mcols(BiocFrame({ "A": [ True, False, False, True ], "B": np.array([0,1,2,3]) }))
print(Y)
## IRanges object with 4 ranges and 2 metadata columns
##         start       end     width        A         B
##     <ndarray> <ndarray> <ndarray>   <list> <ndarray>
## [0]         1        11        10 |   True         0
## [1]         2        22        20 |  False         1
## [2]         3        33        30 |  False         2
## [3]         4        44        40 |   True         3

Z = Y.set_metadata({ "FOO":1, "BAR": 2})
print(Z)
## IRanges object with 4 ranges and 2 metadata columns
##         start       end     width        A         B
##     <ndarray> <ndarray> <ndarray>   <list> <ndarray>
## [0]         1        11        10 |   True         0
## [1]         2        22        20 |  False         1
## [2]         3        33        30 |  False         2
## [3]         4        44        40 |   True         3
## ------
## metadata (2): 'FOO' 'BAR'