Typo in section 2.6.1.

Hello,

There is a typo in section **2.6.1**:

```r
library(data.table)
df.f=d(enhancerFilePath, header = FALSE,data.table=FALSE)
```
 
It shoud say:

```r
library(data.table)
df.f=fread(enhancerFilePath, header = FALSE,data.table=FALSE)
```

Thanks,
Carlos.