Chef shell-init command on windows is having encoding issues and corrupting the $profile

Running the following command with ChefDK 0.14.25 on Win10 with PowerShell v5:

powershell
S:> "chef shell-init powershell | Invoke-Expression" >> $PROFILE

The shell-init command is added to my $profile with null bytes between each character. Launching a new PowerShell session throws error from the $profile.

``` powershell```
S:\> gc $PROFILE
## Import Modules
# Import-Module PSReadLine
# Import-Module PsGet
# Import-Module pscx
## Import Modules end
c h e f   s h e l l - i n i t   p o w e r s h e l l   |   I n v o k e - E x p r e s s i o n

The root issue here is that my $profile file was using ANSI encoding instead of UTF8 or USC2.

One solution is to append with a specific encoding:

powershell
"chef shell-init powershell | Invoke-Expression" | out-file $PROFILE -Encoding utf8 -append

... but then you end up changing the encoding type of the entire file. And that might cause other problems for people. 

[PSVersionTable.txt](https://github.com/chef/chef-dk/files/273469/PSVersionTable.txt)

Reproduce the issue using ChefDK 0.14.25 on Windows 10 with PowerShell 5, running the shown shell-init command against an ANSI-encoded $PROFILE. No repository file or test is named; done means the command no longer inserts null bytes or corrupts the existing profile encoding.