[ETH][ETC] Dag creation error - System.OutOfMemoryException: ethash_full_new IO or memory error
## Note
Since there is a closed issue and #186 , It could be better to have open a new one to review this problem.
Current dev and master branch code fails while ETH and ETC dag creation.
Attaching C++ native projects to the solution  could help other developers( like me) to fix the issue. it's quite hard to debug with preloaded dlls.

### Description

ETH and ETC dag creation stops the node with this error:
System.OutOfMemoryException: ethash_full_new IO or memory error

### Steps to Reproduce

OS: Windows 10 or Windows 2012 Datacenter 
Ram: 12 GB Ram
CPU: 6 Core AMD
Parity v1.10.0-20180320 beta
Parity , Postgres and VS 2017 are installed in the same VMs.

Already tried these options:

**"dagDir": "c:\\eth\\dag\\" 
"dagDir": "c:/eth/dag/",
"dagDir": "/eth/dag/",**

**config.js is below:**
```javascript
{
"logging": {
"level": "info",
"enableConsoleLog": true,
"enableConsoleColors": true,
"logFile": "logtxt.log",
"logBaseDirectory": "",
"perPoolLogFile": true
},
"banning": {
"manager": "integrated",
"banOnJunkReceive": true,
"banOnInvalidShares": false
},
"notifications": {
"enabled": true,
"email": {
"host": "smtp.example.com",
"port": 587,
"user": "user",
"password": "password",
"fromAddress": "info@yourpool.org",
"fromName": "support"
},
"admin": {
"enabled": false,
"emailAddress": "",
"notifyBlockFound": true
}
},
"persistence": {
"postgres": {
"host": "127.0.0.1",
"port": 5432,
"user": "miningcore",
"password": "miningcore",
"database": "miningcore"
}
},
"paymentProcessing": {
"enabled": true,
"interval": 600,
"shareRecoveryFile": "recovered-shares.txt"
},
"pools": [
{
"id": "eth1",
"enabled": true,
"dagDir": "c:\eth\dag\",
"coin": {
"type": "ETH"
},
"address": "0x*******************",
"rewardRecipients": [
{
"type": "op",
"address": "0x*******************",
"percentage": 1
}
],
"blockRefreshInterval": 500,
"clientConnectionTimeout": 600,
"banning": {
"enabled": true,
"time": 600,
"invalidPercent": 50,
"checkThreshold": 50
},
"ports": {
"3072": {
"difficulty": 0.1,
"varDiff": {
"minDiff": 0.05,
"maxDiff": null,
"targetTime": 15,
"retargetTime": 90,
"variancePercent": 30
}
}
},
"daemons": [
{
"host": "127.0.0.1",
"port": 8545,
"user": "user",
"password": "password"
}
],
"paymentProcessing": {
"enabled": true,
"minimumPayment": 0.01,
"minimumPaymentToPaymentId": 5.0,
"payoutScheme": "PPLNS",
"payoutSchemeConfig": {
"factor": 2.0
},
"coinbasePassword": " ",
"keepUncles": false,
"keepTransactionFees": false
}
}
]
}
```

### Expected behavior

Proper DAG creation without error.

### Actual behavior

0 sized DAG created with memory error.

<img width="1121" alt="screen shot 2018-04-25 at 01 47 40" src="https://user-images.githubusercontent.com/1556416/39262158-46d68234-48c7-11e8-8eb5-579790c6e523.png">
<img width="938" alt="screen shot 2018-04-25 at 01 45 13" src="https://user-images.githubusercontent.com/1556416/39262164-49971aec-48c7-11e8-8bf1-277fbf2ebaff.png">
<img width="1273" alt="screen shot 2018-04-25 at 01 43 20" src="https://user-images.githubusercontent.com/1556416/39262167-4ccbfcbe-48c7-11e8-8b96-d5491d6c8d87.png">

