Bump to 0.1.13.
Bump to 0.1.13.

DonSheddow/num,jbcrail/num,Ticki/num,rust-num/num-bigint,vks/num,rust-num/num-traits,rust-num/num-bigint,Gustorn/num,koverstreet/num,rust-lang/num,achanda/num,DonSheddow/num,anchovieshat/num,vks/num,anchovieshat/num,bluss/num,huonw/num,rust-num/num,ollie27/rust_num,rust-num/num-integer,achanda/num,koverstreet/num,rust-lang/num,jdm/num,jbcrail/num,rust-num/num-integer,Emerentius/num,rust-num/num,hauleth/num,rust-num/num-traits